Grid assembly for a plate-shaped battery electrode of an electrochemical accumulator battery

ABSTRACT

The invention relates to a grid arrangement for a plate-shaped battery electrode of an electrochemical accumulator having a frame and a grid arranged thereon, wherein the frame comprises at least one upper frame element having a connecting lug of the battery electrode disposed on its side facing away from the grid, and wherein the grid is at least formed by horizontal bars, which are bars extending substantially horizontally, and vertical bars, which are bars extending substantially vertically, wherein at least some of the vertical bars are arranged at different angles to one another in the shape of a fan. The invention further relates to an accumulator.

The invention relates to a grid arrangement for a plate-shaped battery electrode of an electrochemical accumulator in accordance with the preamble of claim 1. The invention further relates to an accumulator in accordance with claim 7.

Generally speaking, the invention relates to the field of electrochemical accumulators having plate-shaped battery electrodes, also known as electrode plates. Such accumulators are particularly manufactured as lead-acid batteries. Grid arrangements for such battery electrodes are described for example in DE 10 2008 029 386 A1 and WO 01/04977 A1. Such grid arrangements are usually made of lead. Due to rising raw material prices and with the objective of reducing the weight of electrochemical accumulators, minimizing the amount of lead used is desirable.

The invention is thus based on the task of specifying an optimized grid arrangement with which the amount lead needed can be reduced without any impairing of performance.

This task is solved in accordance with claim 1 by a grid arrangement for a plate-shaped battery electrode of an electrochemical accumulator having a frame and a grid arranged thereon, wherein the frame comprises at least one upper frame element having a connecting lug of the battery electrode disposed on its side facing away from the grid, and wherein the grid is at least formed by horizontal bars, which are bars extending substantially horizontally, and vertical bars, which are bars extending substantially vertically, wherein at least some of the vertical bars are arranged at different angles to one another in the shape of a fan, and having at least one, some or all of the following a), b), c), d) features:

-   a) a straight line which runs through the center of gravity of the     grid arrangement and is a parallel to the central axis of the     vertical bar having the shortest distance to the grid arrangement's     center of gravity, passes the connecting lug at a distance of less     than 15%, in particular less than 10%, of the connecting lug width,     or intersects the connecting lug, -   b) a straight line which runs through the center of gravity of the     grid arrangement and is a parallel to the central axis of the     vertical bar having the shortest distance to the grid arrangement's     center of gravity, intersecting the upper frame element at a point     which is less than 15%, particularly less than 10%, of the length of     the upper frame element away from a vertical central axis of the     connecting lug, -   c) the sum of all the angles of those vertical bars which intersect     both the upper as well as the lower frame element of the grid     arrangement, or at least would intersect in mathematical extension,     is greater than 7°, wherein the angles are defined in terms of an     axis extending exactly vertically, -   d) the sum of the angles of the outermost left and outermost right     vertical bar intersecting both the upper as well as the lower frame     element of the grid arrangement, or at least would intersect in     mathematical extension, is greater than 7°, wherein the angles are     defined in terms of an axis extending exactly vertically.

In simplified terms, the grid arrangement according to the invention distinguishes itself from known grid arrangements by the arrangement of the vertical bars as a whole being canted or tilted toward the connecting lug. This enables on the one hand the desired material savings in raw lead material, along with the accompanying weight savings, and additionally, despite economizing on the raw material, even further improved electrical conductivity. The inventive grid arrangement thus enables the providing of an accumulator which weighs less than known accumulators and yet exhibits better electrical performance data.

The cited modified spatial orientation of the vertical bars can be rendered pursuant to one, multiple or all of the a), b), c), d) features of claim 1.

As per feature a) and b), a straight line is thereby defined through which the grid arrangement's center of gravity runs. The grid arrangement's center of gravity is to be understood, as commonly accepted in physics, as the center of mass of the grid arrangement, including the connecting lug. The center of mass of a body is the mass-weighted average of its mass point positions. The grid arrangement is usually made of relatively homogeneous lead material such that the center of mass then also corresponds to the geometrical center of gravity. The cited straight line running through the grid arrangement's center of gravity is moreover a parallel to the central axis of the vertical bar at the shortest distance from the grid arrangement's center of gravity. Thus, the vertical bar situated closest to the center of gravity needs to be determined; the cited straight line is a parallel to its central axis. The central axis is the longitudinal axis of the vertical bar, so to speak, that which runs dead center along the vertical bar in the longitudinal direction, thus substantially vertically. The central axis can inasmuch also be referred to as bisecting the vertical bar.

According to feature a), the straight line can pass the connecting lug at a certain distance or intersect it. If the straight line passes the connecting lug, it has no point of intersection with the connecting lug. According to feature b), the defined straight line similarly intersects the upper frame element at a specific point defined in relation to the vertical central axis of the connecting lug as previously clarified. To be understood as the vertical central axis in this case is an axis running exactly vertically at the dead center of the connecting lug.

Insofar as the usage of terms such as horizontally, vertically, above, below and/or horizontal or vertical, these terms refers to the mounting orientation of the battery electrode in an electrochemical accumulator when in normal position for specification-compliant use. As a rule, the specification-compliant normal position of the accumulator is with the bottom of the accumulator being in a horizontal position.

Where angles are specified in degrees (e.g. 7°), the specifications refer to an overall circular dimension of 360°.

According to one advantageous further development of the invention, the vertical bars arranged in the manner of a fan exhibit an angular difference of less than 5° between adjacent vertical bars. This allows further optimizing of the grid arrangement in terms of electrical performance as well as the material quantity and thus the weight.

According to one advantageous further development of the invention, the connecting lug is arranged asymmetrically on the upper frame element. The connecting lug has a first vertical side, disposed on the side of the longer leg of the upper frame element, whereby the straight line according to feature a) of claim 1 passes or intersects the connecting lug at its first vertical side and/or the point at which the straight line according to feature b) of claim 1 intersects the upper frame element is situated in the region of the upper frame element's longer leg. This thereby further optimizes the electrical conductivity as well as the need for material and the weight of the grid arrangement. The cited straight line is then situated on the side of the connecting lug's inner lug corner as it were; i.e. the corner facing the longer leg of the upper frame element.

According to one advantageous further development of the invention, the grid arrangement is a stamped lead grid. According to one advantageous further development of the invention, the grid arrangement is designed as a positive grid arrangement for a positive battery electrode.

The grid arrangement at least comprises the upper frame element. The grid arrangement can additionally comprise a lower frame element, a left as well as a right frame element, wherein the upper frame element is connected to the lower frame element by means of the left and right side frame elements. The grid is thereby arranged with the frame. Doing so provides a grid arrangement of increased robustness including in its lower regions.

The task cited at the outset is additionally solved pursuant to claim 7 by an accumulator having a plurality of plate-shaped battery electrodes arranged into one or more electrode plate packs, wherein one, multiple or all of the battery electrodes comprise a grid arrangement in accordance with one of the preceding claims.

The following will reference the drawings in describing the invention in greater detail by way of embodiments. Shown are:

FIG. 1: a semi-exploded view of an accumulator and its structural elements;

FIG. 2: a grid arrangement;

FIG. 3: a grid arrangement provided with an active mass;

FIG. 4: the encasing of a grid arrangement provided with an active mass within a separator;

FIG. 5: a top view of the grid arrangement according to the invention; and

FIG. 6: a top view of a further inventive grid arrangement.

The figures make use of the same reference numerals for equivalent elements.

FIG. 1 illustrates an example basic design of an accumulator 100 according to the invention. The accumulator 100 can in particular be designed as a lead-acid battery having liquid electrolyte, for example in the form of sulfuric acid. The accumulator 100 has a housing 110 in which or more or more plate packs 107 are arranged. The accumulator 100 has a fixed number of plate packs 107 based on its number of cells. The plate packs 107 are respectively arranged in individual holding chambers of the housing 110 separated from one another by partitions. The plate packs 107 are connected together into a series connection within the housing 110 by internal connecting elements not depicted in FIG. 1. The positive plates at the one end of the plate pack and the negative plates at the other end of the plate pack are electrically connected to respective external terminals 108, 109 located in a cover part 111 of the accumulator housing 110. The electrical energy of the accumulator 100 is supplied to electrical loads through terminals 108, 109.

The plate packs 107 comprise respectively alternating positive and negative electrode plates. The negative electrode plates are depicted as negative plate group 115, the positive electrode plates as positive plate group 114. FIG. 1 includes a depiction of individual electrode plates for illustrative purposes; i.e. a negative electrode plate 105 comprising a negative flat lead grid 102 and a positive electrode plate 104 comprising a positive flat lead grid 101. The positive electrode plate 104 and the negative electrode plate 105 depicted in FIG. 1 already exhibit a pasting with active mass, same covering the individual grid bars and cutouts. The positive and/or negative lead grid comprise(s) a plurality of grid bars and a plurality of window-like cutouts formed between the grid bars. The positive and/or negative lead grid 101, 102 can be produced for example in a stamping process or by means of other methods such as casting and/or rolling.

The positive electrode plate 104 is additionally separated from the negative electrode plate 105 by a separator material 106. The separator material 106 can in particular be formed into the shape of a pouch to accommodate the positive electrode plate 104 and separate it from adjacent electrode plates.

The positive electrode plates 104 each comprise a respective connecting lug 103 by means of which the electrode plates in the positive plate group 114 are connected together into a parallel connection. The negative electrode plates 105 each comprise a respective connecting lug 103 by means of which the electrode plates in the negative plate group 115 are connected together into a parallel connection. The connection can be made by a connector 112 soldered or welded onto the connecting lugs 103 as is recognizable in FIG. 1.

The accumulator 100 according to FIG. 1 can in particular comprise one or more inventive electrode plates, e.g. in the form of positive electrode plates 104.

FIG. 2 shows an example of a positive lead grid 101 in a top plan view. It can be seen that the lead grid 101 has a plurality of grid bars 114, between which is a plurality of window-like cutouts 113. To make it easier to handle and for purposes of mechanical stability as well as improved electrical properties, the outer edge of the lead grid 101 can exhibit one, some or all of the following cited frame sections: upper frame section 115, left side frame section 119, lower frame section 117, right side frame section 118.

FIG. 3 shows the lead grid 101 from FIG. 2 after having been at least partly covered with active mass, which is usually applied in paste form. This process is also known as pasting. FIG. 4 shows the lead grid 103 of FIG. 3 having been provided with the active mass being inserted into a wrapper-like separator 106.

FIG. 5 shows a grid arrangement 101 formed according to the invention, again comprising a frame having an upper frame element 120, a lower frame element 117, a right side frame element 118 and a left side frame element 119. The grid 113 is situated within the area enclosed by the above-cited frame elements. As can be seen, the connecting lug 103 disposed on the upper frame element 120 is arranged asymmetrically on the upper frame element 120, somewhat to the right of the grid arrangement center. A vertical central axis A running exactly vertical intersects the center of the connecting lug 103. The vertical central axis A thereby also serves as a vertical reference axis.

Further reference numerals are provided in FIG. 5 to specify the grid 113 in greater detail. The grid 113 comprises a plurality of horizontal bars; of these, horizontal bars 21 to 25 have been provided with reference numerals for illustrative purposes. The horizontal bars extend substantially horizontally. Vertical bars intersect or cross or are tangent to the horizontal bars. Of the vertical bars, vertical bars 9 to 20 have been provided with reference numerals for illustrative purposes. The vertical bars do not run exactly vertically but rather at different angles to each other in the shape of a fan, whereby they radiate outwardly from the upper frame element 120. The vertical bars identified by reference numerals 9 to 20 intersect both the upper frame element as well as, at least in a mathematical extension, the lower frame element 117. Further vertical bars arranged to the left and right thereof, which are not provided with reference numerals, do not intersect the lower frame element 117, not even in a mathematical extension.

It is provided with the grid arrangement according to the invention for the sum of all the angles of the vertical bars 9 to 20; i.e. the vertical bars intersecting both the upper as well as the lower frame element of the grid arrangement, or at least intersecting in mathematical extension, to be greater than 7°. The angles are defined here with respect to the vertical reference axis A. This results in the sum of all the angles being approximately equivalent to the intersecting angle of central axis M with vertical reference axis A. In other words, the angle of inclination to the vertical reference axis A yielded by the summation is a value greater than 7°.

In corresponding manner, the inventive grid arrangement also exhibits a value greater than 7°, again relative to the vertically extending reference axis A, with respect to the sum of the angles of the outermost left vertical bar 9 and the outermost right vertical bar 20 which intersect both the upper and well as the lower frame element of the grid arrangement, or at least would intersect in mathematical extension.

The connecting lug 103 has a first vertical side 2 arranged on the side of the longer leg 3 of the upper frame element 120. An opposite second vertical side 4 is arranged on the side of the shorter leg 5 of the upper frame element 120. The legs 3, 5 are formed to the respective left and right of the connecting lug 103.

The center of gravity S is plotted in the grid arrangement according to FIG. 5. Vertical bar 14 is the vertical bar situated closest the center of gravity S; i.e. the vertical bar having the least distance from the center of gravity S. The central axis M of vertical bar 14 is also plotted in FIG. 5. A parallel to central axis M running through the center of gravity S is further plotted as straight line G. Said straight line G passes the connecting lug 103 on the first vertical side 2 at a distance D. In the grid arrangement according to the invention, the straight line G can also intersect the connecting lug 103, particularly in the area of the first vertical side 2. The intersecting point can also be situated at other locations on the connecting lug 103, ranging to the second vertical side 4 of the connecting lug 103 opposite from the first vertical side 2.

It can further be provided in the inventive grid arrangement for a point 1 at which the straight line G intersects the upper frame element 120 to be situated at a distance less than 15%, in particular less than 10% of the length L of the upper frame element 120 from the vertical central axis A of the connecting lug 103. The length L of the upper frame element 120, which also concurrently corresponds to the width of the grid arrangement 101, is plotted in FIG. 5. The width B of the connecting lug 103 is likewise plotted.

FIG. 6 shows a further inventive grid arrangement 101 having a narrower structure than the embodiment according to FIG. 5. The length L of the upper frame element is thus shorter than in the embodiment according to FIG. 5. Because of the shorter total width, the grid arrangement 101 according to FIG. 6 has fewer vertical bars. Among the vertical bars, only vertical bars 9, 10, 11, 14, 17, 18, 19 and 20 intersect the upper frame element and, at least in mathematical extension, also the lower frame element 117. Of this subset of vertical bars, vertical bar 9 is again the outermost left vertical bar and vertical bar 20 the outermost right vertical bar. Further vertical bars not provided with reference numerals are arranged to the left and right of this subset of vertical bars and also do not intersect the lower frame element 117 in extension. In the embodiment according to FIG. 6, vertical bar 14 is again the vertical bar situated closest to the center of gravity S of the grid arrangement 101.

The reference numerals of FIG. 6 otherwise correspond to those of FIG. 5.

To aid in identification, FIG. 6 also separately plots, to the right of the grid arrangement, the arrangement of the center of gravity S, central axis M and straight line G as well as the distance D from the connecting lug 103 without the grid bars. The course of straight line G in the left part of FIG. 6 is somewhat hard to distinguish due to part of it running along the edge of vertical bar 14.

The embodiments according to FIGS. 5 and 6 document the universal applicability of the present invention. 

1. A grid arrangement (101, 102) for a plate-shaped battery electrode (104, 105) of an electrochemical accumulator (100), having a frame (117, 118, 119, 120) and a grid (113) arranged thereon, wherein the frame (117, 118, 119, 120) comprises at least one upper frame element (120) having a connecting lug (103) of the battery electrode (104, 105) disposed on its side facing away from the grid (113), and wherein the grid (113) is at least formed by horizontal bars (21 to 25), which are bars extending substantially horizontally, and vertical bars (9 to 20), which are bars extending substantially vertically, wherein at least some of the vertical bars (9 to 20) are arranged at different angles to one another in the shape of a fan, characterized by at least one, some or all of the following a), b), c), d) features: a) a straight line (G), which runs through the center of gravity of the grid arrangement (101, 102) and is a parallel to the central axis (M) of the vertical bar (14) having the shortest distance to the center of gravity (S) of the grid arrangement (101, 102), passes the connecting lug (103) at a distance (D) of less than 15%, in particular less than 10%, of the connecting lug width (B), or intersects the connecting lug (103), b) a straight line (G) which runs through the center of gravity of the grid arrangement (101, 102) and is a parallel to the central axis (M) of the vertical bar (14) having the shortest distance to the center of gravity (S) of the grid arrangement (101, 102), intersecting the upper frame element (120) at a point (1) which is less than 15%, particularly less than 10%, of the length (L) of the upper frame element (120) away from a vertical central axis (A) of the connecting lug (103), c) the sum of all the angles of those vertical bars (9 to 20) which intersect both the upper as well as the lower frame element (120) of the grid arrangement (101, 102), or at least would intersect in mathematical extension, is greater than 7°, wherein the angles are defined in terms of an axis (A) extending exactly vertically, d) the sum of the angles of the outermost left and outermost right vertical bar (10, 20) intersecting both the upper as well as the lower frame element (120) of the grid arrangement (101, 102), or at least would intersect in mathematical extension, is greater than 7°, wherein the angles are defined in terms of an axis (A) extending exactly vertically.
 2. The grid arrangement according to claim 1, characterized in that the vertical bars (9 to 20) arranged in the manner of a fan exhibit an angular difference of less than 5° between adjacent vertical bars.
 3. The grid arrangement according to claim 1, characterized in that the connecting lug (103) is arranged asymmetrically on the upper frame element (120) and has a first vertical side (2) disposed on the side of the longer leg (3) of the upper frame element (120), wherein the straight line (G) according to feature a) of claim 1 passes or intersects the connecting lug (103) at its first vertical side (2) and/or the point (1) at which the straight line (G) according to feature b) of claim 1 intersects the upper frame element is situated in the region of the longer leg (3) of the upper frame element (120).
 4. The grid arrangement according to claim 1, characterized in that the grid arrangement (101, 102) is a stamped lead grid.
 5. The grid arrangement according to claim 1, characterized in that the grid arrangement (101, 102) is designed as a positive grid arrangement for a positive battery electrode (104, 105).
 6. The grid arrangement according to claim 1, characterized in that the frame (117, 118, 119, 120) comprises the upper frame element (120), a lower frame element (117) and a left and a right side frame element (118, 119), wherein the upper frame element (120) is connected to the lower frame element (117) by means of the left and right side frame elements (118, 119), wherein the grid (113) is disposed with the frame (117, 118, 119, 120).
 7. An accumulator (100) having a plurality of plate-shaped battery electrodes (104, 105) arranged into one or more electrode plate packs (107), wherein one, multiple or all of the battery electrodes (104, 105) comprise a grid arrangement (101, 102) in accordance with claim
 1. 